This invention relates to novel catalysts useful in processes for the fluorination of hydrocarbons (halogenated or unsaturated), especially to supported Lewis acid catalysts such as antimony on fluorinated carbon which are useful at higher temperatures in such fluorination processes.
The art (for example, U.S. Pat. Nos. 5,449,842; 5,208,395; and 2,749,374) has disclosed the use of Lewis acid catalysts such as antimony (V) to catalyze fluorination processes involving the electrophilic addition of HF to unsaturated hydrocarbons or the replacement of a halogenated hydrocarbon's (non-fluorine) halogen atoms with fluorine atoms. However, in processes where the reaction temperature is greater than 150.degree. C., antimony V is reduced to antimony III resulting in catalyst deactivation. Attempts to address this problem (as in the aforementioned U.S. Pat. No. 2,749,374) have involved the continuous feeding of low levels of chlorine to maintain antimony catalyst in the +5 oxidation state; this, however, causes the formation of undesirable chlorinated coproducts, which require separation and hence additional processing complications.
What is desired is a catalyst for use in fluorination processes which can withstand higher temperatures without the need for introducing additional cofeeds such as chlorine.